The production of syngas from the solid and liquid carbonaceous fuels, especially coal, coke, and liquid hydrocarbon feeds, has been utilized for a considerable period of time and has recently undergone significant improvements due to the increased energy demand. Syngas may be produced by heating carbonaceous fuels with reactive gases, such as air or oxygen, often in the presence of steam in a gasification reactor to obtain the fuel gas which is withdrawn from the gasification reactor. The syngas is then subjected to several cleansing operations to rid it of various contaminants which are formed or liberated from the feed during the gasification operation. These materials can readily become contaminate down stream process units if not properly treated during the gasification operation.
For example, materials often found in the syngas include hydrogen sulfide, ammonia, cyanides, and particulates in the form of carbon and trace metals. The extent of the contaminants in the feed is determined by the type of feed and the particular gasification process utilized as well as the operating conditions. In any event, the removal of these contaminants is critical to make gasification a viable process.
As the product gas is discharged from the gasifier, it is usually subjected to a cooling and cleaning operation involving a scrubbing technique wherein the gas is introduced into a scrubber and contacted with a water spray which cools the gas and removes particulates and ionic constituents from the syngas. The initially cooled gas may then be treated to desulfurize the gas prior to utilization of the product gas.